Vent assembly and method for a digital valve positioner

ABSTRACT

A digital valve positioner for use with an actuator. The digital valve positioner includes a housing, at least one exhaust port opening formed in the housing, and a vent assembly operatively coupled to the at least one exhaust port opening. The vent assembly includes a body having a bore, a valve seat surrounding the bore, and a check valve disposed within the bore. The check valve is arranged to shift from a closed position seated against the valve seat to an open position disposed away from the valve seat. A plurality of barriers is disposed around and positioned to enclose the check valve. The plurality of barriers is arranged to prevent an external medium from entering the check valve and to provide a tortuous flow path for the exhaust medium reducing sound through the vent assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.14/701,072, filed Apr. 30, 2015, which claims the benefit of U.S.Provisional Application No. 61/987,419, filed May 1, 2014, both of whichare hereby incorporated by reference in their entirety herein.

FIELD OF THE DISCLOSURE

The present invention relates generally to digital valve positioners,and, more specifically, to a vent assembly for a high capacity digitalvalve positioner.

BACKGROUND OF THE DISCLOSURE

Distributed process control systems, like those used in chemical,petroleum or other processes, typically include one or more processcontrollers communicatively coupled to one or more field devices viaanalog, digital or combined analog/digital buses. The field devices,which may be, for example, valves, valve positioners, e.g., digitalvalve positioners, and transmitters, e.g., temperature, pressure, leveland flow rate sensors, are located within the process environment andperform process functions such as opening or closing valves andmeasuring process parameters. Smart field devices, such as the fielddevices conforming to the well known FOUNDATION® Fieldbus protocol mayalso perform control calculations, alarming functions, and other controlfunctions commonly implemented within the controller. The processcontrollers receive signals indicative of process measurements made bythe field devices and/or other information pertaining to the fielddevices. The controller then executes a controller application thatruns, for example, different control modules which make process controldecisions, generate control signals based on the received informationand coordinate with the control modules or blocks being performed in thefield devices, such as HART and Fieldbus field devices. The controlmodules in the controller send the control signals over thecommunication lines to the field devices to thereby control theoperation of the process plant.

More specifically, a process control network or system includes one ormore process controllers connected to one or more host workstations orcomputers (which may be any type of personal computer, workstation orother computer) and to a data historian via a communication connection.The communication connection may be, for example, an Ethernetcommunication network or any other desired type of private or publiccommunication network. Each of the controllers is connected to one ormore input/output (I/O) devices each of which, in turn, is connected toone or more field devices, such as a digital valve positioner. As one ofskill in the art will appreciate, the process control system couldinclude any other number of controllers and any desired number and typesof field devices. Of course, the controllers are communicativelyconnected to the field devices using any desired hardware and softwareassociated with, for example, standard 4-20 ma devices and/or any smartcommunication protocol such as the Fieldbus or HART protocols. As isgenerally known, the controllers, which may be, by way of example only,DeltaV™ controllers sold by Fisher Rosemount Systems, Inc., implement oroversee process control routines or control modules stored therein orotherwise associated therewith and communicate with the devices tocontrol a process in any desired manner.

As noted, an exemplary field instrument of the process control system isthe digital valve positioner. As is well known to persons havingordinary skill in the art, the digital valve positioner converts aninput current signal into a pneumatic output pressure to an actuator towhich the digital valve positioner is operatively coupled. In additionto this normal function, the digital valve positioner also uses acommunications protocol, such as the HART communications protocol, togive easy access to information critical to the process operation. Inone example, the digital valve positioner provides comprehensive valvediagnostic alerts that are easily accessed via a field communicator anddelivers notification of current or potential equipment issues to anasset management system. For example, the alerts assist inidentification and notification of several situations including: (1)valve travel deviation due to excess valve friction or galling; and (2)valve travel above or below a specified point. The alerts are stored ina memory on board the digital valve positioner.

One trend in the digital valve positioner market specifically, and theelectro-pneumatic instrument market generally, is to design instrumentswith significantly greater flow capacities than conventionalinstruments. For example, conventional digital valve positionerstypically have a flow coefficient (Cv) of 0.3, while higher flowcapacity digital valve positioners have a flow coefficient (Cv) rangingfrom 1.2 to 6.4. This higher flow capability means that the pneumaticporting in the product, e.g., supply porting, output porting, andexhaust porting, has to be significantly larger than conventionaldigital valve positioners, for example.

Such larger porting, however, can lead to a greater chance for dirt andmoisture and any other external medium in the environment to migrateinto the digital valve positioner, which can adversely affect theoperation of internal devices of the digital valve positioner.Specifically, the exhaust ports of the digital valve positioner areprime areas where dirt and moisture and other external media can enterthe digital valve positioner. In addition, higher flow rates of thehigher capacity digital valve positioner generate more noise, such thatthe noise levels are directly increasing in proportion to the increasingflow rate.

SUMMARY OF THE DISCLOSURE

In accordance with a first exemplary aspect of the disclosure, a digitalvalve positioner for use with an actuator is disclosed. The digitalvalve positioner includes a housing, at least one exhaust port openingformed in the housing, and a vent assembly operatively coupled to the atleast one exhaust port opening. The vent assembly includes a bodyoperatively coupled to the at least one exhaust port opening, the bodyincluding a bore, and a valve seat surrounding the bore. A check valveis disposed within the bore, the check valve arranged to shift from aclosed position seated against the valve seat to an open positiondisposed away from the valve seat when an exhaust medium flows throughthe at least one exhaust port opening. In addition, a plurality ofbarriers is disposed around the check valve and positioned to enclosethe check valve, the plurality of barriers arranged to prevent anexternal medium from entering the check valve and to provide a tortuousflow path for the exhaust medium reducing sound through the ventassembly.

According to another exemplary aspect of the present disclosure, adigital valve positioner for use with an actuator is disclosed, thedigital valve positioner comprising a housing, at least one exhaust portopening formed in the housing, and a vent assembly operatively coupledto the at least one exhaust port opening. The vent assembly includes abody operatively coupled to the at least one exhaust port opening, thebody including a bore, and a valve seat surrounding the bore. A checkvalve is disposed within the bore, the check valve arranged to shiftfrom a closed position seated against the valve seat to an open positiondisposed away from the valve seat when an exhaust medium flows throughthe at least one exhaust port opening. In addition, a cap is removablysecured to the body, the cap having a plurality of barriers extendingtherefrom and disposed around the check valve to enclose the checkvalve, the cap and the plurality of barriers arranged to prevent anexternal medium from entering the check valve and to provide a tortuousflow path for the exhaust medium reducing sound through the ventassembly.

According to a further exemplary aspect of the present disclosure, avent assembly for a digital valve positioner operatively coupled to anactuator is disclosed. The vent assembly comprises a body having aninlet, an outlet, a bore disposed between the inlet and the outlet, aplurality of apertures surrounding the bore, and a valve seatsurrounding the plurality of apertures. The body is adapted to beoperatively secured to an exhaust port opening of the digital valvepositioner. The vent assembly further comprises an umbrella valvedisposed within the bore, the umbrella valve biased in a closedposition, such that the umbrella valve is shiftable between the closedposition seated against the valve seat and an open position disposedaway from the valve seat when an exhaust medium flows through the inletof the body. In addition, an enclosure is disposed around the umbrellavalve and positioned to enclose the umbrella valve, the enclosurecomprising a plurality of barriers arranged to prevent an externalmedium from entering the umbrella valve and to provide a tortuous flowpath for the exhaust medium reducing sound through the vent assemblywithout affecting flow capacity.

According to yet another exemplary aspect, a method of venting a digitalvalve positioner operatively coupled to an actuator is disclosed. Thedigital valve positioner comprises a housing and at least one exhaustport opening formed in the housing. The method comprises providing avent assembly comprising a check valve surrounded by a plurality ofbarriers and operatively securing the vent assembly to the at least oneexhaust port opening. The method further comprises directing an exhaustmedium into the check valve and through the plurality of barriers,reducing the sound of the exhaust medium flowing through the ventassembly, and preventing an external medium from entering the checkvalve without affecting the flow capacity of the digital valvepositioner.

In further accordance with any one or more of the exemplary aspects, adigital valve positioner, an actuator, and/or a vent assembly of thisdisclosure optionally may include any one or more of the followingfurther preferred forms.

In some preferred forms, the body is disposed over the at least oneexhaust port and includes an outer end surface. The body may define aninlet, an outlet and a bore disposed between the inlet and the outlet.In addition, a plurality of apertures may be disposed in the outer endsurface and around the bore. The at least one exhaust port opening maycomprise two exhaust port openings, and the body may be disposed overthe at least two exhaust port openings. Each barrier of the plurality ofbarriers may include an elongate protrusion extending from the outer endsurface of the body and having a first end and a second end. At leastone of the first and second ends overlaps with one or more of the firstand second ends of another elongate protrusion of the plurality ofbarriers to enclose the check valve. The vent assembly may furthercomprise a cap disposed over the plurality of barriers to furtherenclose the check valve and reduce sound through the vent assembly, anda screen may be disposed between the body and the cap, the screenallowing the exhaust medium flowing through the plurality of barriers tobe released to the atmosphere. The check valve may comprise an umbrellacheck valve. The check valve is positioned in the closed position, suchthat when the exhaust medium flows through the at least one exhaust portopening, the exhaust medium is directed through the plurality ofapertures and into the check valve, shifting the check valve to the openposition to release exhaust medium through the plurality of barriers andinto the atmosphere.

In some preferred forms, the body may further include a second bore, asecond valve seat surrounding the second bore, and a second check valvedisposed within the bore. The second check valve is arranged to shiftfrom a closed position seated against the valve seat to an open positiondisposed away from the valve seat when the exhaust medium flows throughthe at least one exhaust opening. The plurality of barriers is disposedaround the second check valve and positioned to enclose the second checkvalve, preventing the external medium from entering the second checkvalve.

In some preferred forms, the cap comprises a top face and a bottom face,and the bottom face has a concave section adapted to receive the checkvalve when the check valve is in an open position. The plurality ofbarriers may comprise a plurality of posts, and the plurality of postsextends from the bottom face and surrounds the check valve. Each post ofthe plurality of posts is offset from the other posts to enclose thecheck valve and to provide no line-of-sight between the external mediumand the check valve.

Additional optional aspects and features are disclosed, which may bearranged in any functionally appropriate manner, either alone or in anyfunctionally viable combination, consistent with the teachings of thedisclosure. Other aspects and advantages will become apparent uponconsideration of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a digital valve positioner of thepresent disclosure operatively coupled to an actuator;

FIG. 2 is a front perspective view of the digital valve positioner ofFIG. 1, the digital valve positioner having a vent assembly according toone aspect of the present disclosure;

FIG. 3 is a rear perspective view of the digital valve positioner ofFIG. 2;

FIG. 4 is a rear perspective view of the digital valve positioner ofFIG. 2, the digital valve positioner having the vent assembly removedtherefrom;

FIG. 5 is a rear perspective view of the digital valve positioner ofFIG. 2 having a partially exploded view of the vent assembly of thepresent disclosure;

FIG. 6 is a top perspective view of a body of the vent assembly of thepresent disclosure;

FIG. 7 is a cross-sectional view of the body of the vent assembly ofFIG. 6 taken along lines A-A of FIG. 6;

FIG. 8 is a perspective view of another example vent assembly accordingto another aspect of the present disclosure, the vent assembly adaptedto be operatively coupled to the digital valve positioner of FIG. 4;

FIG. 9 is an exploded view of the vent assembly of FIG. 8;

FIG. 10 is a bottom perspective view of a cap of the vent assembly ofFIG. 8;

FIG. 11 is a perspective view of a digital valve positioner havinganother vent assembly according to yet another aspect of the presentdisclosure;

FIG. 12 is a side perspective view of the digital valve positioner ofFIG. 11;

FIG. 13 is a rear perspective view of the digital valve positioner ofFIG. 11, the digital valve positioner of the vent assembly removedtherefrom;

FIG. 14 is a rear perspective view of the digital valve positioner ofFIG. 11 having a partially exploded view of the vent assembly;

FIG. 15 is another rear perspective view of the digital valve positionerof FIG. 11 having an exploded view of the vent assembly; and

FIG. 16 is a cross-sectional view of the vent assembly of FIG. 12, takenalong the line B-B of FIG. 12.

DETAILED DESCRIPTION OF THE DISCLOSURE

Generally, a digital valve positioner for use with an actuator isdisclosed. The digital valve positioner includes a housing, at least oneexhaust port opening formed in the housing, and a vent assemblyoperatively coupled to the at least one exhaust port opening. Asexplained in more detail below, the vent assembly both protects theexhaust port opening from the ingress of any external medium, such asdirt, moisture, rain, wind, hail or other external material in theenvironment, and reduces the noise levels generated by high flow of anexhaust medium through the exhaust port. The vent assembly achieves suchbenefits without affecting the flow capacity of the digital valvepositioner.

Referring now to FIG. 1, an exemplary field instrument 10 mounted to avalve actuator 12 is depicted. The field instrument 10 may be anelectro-pneumatic field instrument, such as a digital valve positioner14. The digital valve positioner 14 includes a main cover 16, apneumatic relay assembly (not shown) disposed under the cover 16, an I/Pmodule or converter (not shown) also disposed under the cover 16, gauges22, an electronics module (not shown), a main housing 26, a terminal box28, and a terminal box cover 30. The digital valve positioner 14converts an input current signal, such as a two-wire 4-20 mA controlsignal, into a pneumatic output pressure to the actuator 12.

Referring now to FIGS. 2-4, the digital valve positioner 14 furtherincludes a porting block 36 having two output ports 38A and 38B and asupply port 40. The output ports 38A, 38B are operatively coupled to theactuator 12 in a known manner. In addition, the supply port 40 isoperatively coupled to a supply source 20 (FIG. 1). Said another way,the supply port 40 is arranged to be connected to the supply source 20(FIG. 1) in a known manner and is depicted in schematic form only inFIG. 1.

As further depicted in FIG. 4, the porting block 36 further includes twoexhaust ports 42A and 42B that correspond to the output ports 38A and38B, respectively. In other words, each output port 38A and 38B has acorresponding exhaust port 42A and 42B. In addition, each exhaust port42A and 42B includes an exhaust port opening 44A, 44B. The porting sizeof each of the output ports 38A, 38B, supply port 40 and exhaust ports42A and 42B, and, therefore, the digital valve positioner 14, canaccommodate higher flow capacity having a flow coefficient (Cv) of anyvalue included in the range of 1.2 through 3.2. As further depicted ineach of FIGS. 2 and 3, the digital valve positioner 14 also includes avent assembly 100 that is operatively coupled to at least one exhaustport opening 44A, 44B, as explained in more detail below. In oneexample, and as depicted in FIG. 3, the vent assembly is operativelycoupled to both exhaust port openings 44A, 44B.

Referring now to FIGS. 5-7, the vent assembly 100 includes a body 102that is operatively coupled to at least one exhaust port opening 44A,44B. The body 102 includes a bore 104, a valve seat 106 surrounding thebore 104, and a check valve 108 disposed within the bore 104. The checkvalve 108 is arranged to shift from a closed position seated against thevalve seat 106 (FIG. 7) to an open position disposed away from the valveseat 106 when the exhaust medium flows through the at least one exhaustport opening 44A, 44B. Said another way, the check valve 108 is normallybiased in the closed position depicted in FIGS. 6 and 7, and will shiftto an open position when the exhaust medium flows into the check valve108. This pushes the check valve 108 away from the valve seat 106 andallows the exhaust medium to vent through the vent assembly 100. Thenormally closed position of the check valve 108 helps protect againstingress of dirt and moisture, for example, into the check valve 108, theexhaust port opening 44A, 44B and, thus, the digital valve positioner14, as explained more below. The body 102 further includes an outer endsurface 110, a portion of which may form the valve seat 106, asdepicted, for example, in FIGS. 5 and 7.

As further depicted in FIG. 7, the body 102 of the vent assembly 100further includes an inlet 112 and an outlet 114. The bore 104 isdisposed between the inlet 112 and the outlet 114, and a plurality ofapertures 116 is disposed in the outer end surface 110 of the body,around the bore 104. The check valve 108 is positioned in the closedposition, such that when the exhaust medium flows through the at leastone exhaust port opening 44A, 44B, the exhaust medium is directedthrough the plurality of apertures 116 surrounding the bore 104 and intothe check valve 108. This shifts the check valve 108 to the openposition to release the exhaust medium to the atmosphere.

The vent assembly 100 further includes an enclosure disposed around thecheck valve 108. In one example, the enclosure comprises a plurality ofbarriers 118. The plurality of barriers 118 is disposed around the checkvalve 108 and positioned to enclose the check valve 108. In addition,the plurality of barriers 118 is arranged to prevent an external medium,such as wind, rain, dirt or any other product from the environment, fromentering the exhaust port openings 44A, 44B through the check valve 108.More specifically, while the check valve 108 is normally biased in theclosed position in which the check valve 108 is seated against the valveseat 106, a shut off force of the check valve 108 is typically light bydesign and, therefore, the check valve 108 may be inadvertently openedif directly impinged by an external medium, such as water or wind. Thus,the plurality of barriers 118 protect the check valve 108 from suchexternal media by enclosing the check valve 108 and still allowing forflow of the exhaust medium without reducing or affecting the flowcapacity of the digital valve positioner 114.

More specifically, and in the example of FIG. 6, each barrier 118 of theplurality of barriers 118 includes an elongate protrusion 120 extendingfrom the outer end surface 110 of the body 102. In addition, eachelongate protrusion 120 may also be curved. Each elongate protrusion 120includes a first end 122 and a second end 124. At least one of the firstand second ends 122, 124 of one protrusion 120 overlaps with one or moreof the first and second ends 122, 124 of another protrusion 120 toenclose the check valve 108. The overlapping protrusions 120 of theplurality of barriers 118 provide no line-of-sight between the checkvalve 108 and an exterior of the body 102 of the vent assembly 100. As aresult, direct impingement of any external media, such as rain, wind, orhail, on the check valve 108 is eliminated. As further depicted in FIG.6, the barriers 118 are also spaced from each other to allow properventing of exhaust medium from the digital valve positioner 14 whenrequired.

While in the foregoing example each barrier 118 of the plurality ofbarriers 118 includes an elongate protrusion 120, each barrier 118 ofthe plurality of barriers 118 may take the shape of a variety of otherforms and still fall within the scope of the present disclosure. Forexample, each barrier 118 of the plurality of barriers 118 mayalternatively form a discrete post, each of which is offset from anotherpost such that no line-of-sight is provided between the check valve 108and an exterior of the body 102 of the vent assembly 100. In yet anotherexample, each barrier 118 of the plurality of barriers 118 may take theform of any other overlapping or offset shape, size or structure andstill fall within the scope of the present disclosure.

Further, noise generated by the exhaust medium flowing through theexhaust port openings 44A, 44B, for example, is reduced by directing theexhaust medium into the plurality of barriers 118. More specifically,the vent assembly 100, and in particular, the check valve 108 directingthe exhaust medium radially into the plurality of barriers 118, forexample, prevents a high velocity exhaust medium, such as air, fromforming at an exit of the exhaust port 42A, 42B of the digital valvepositioner 14. The high velocity exhaust medium instead is shifted to anarea of the check valve 108, which radially directs the exhaust mediumoutwards and together with the plurality of barriers 118 slows theexhaust medium before it exits to the atmosphere. The plurality ofbarriers 118 limits the transmission of sound through the vent assembly100 while still allowing the exhaust medium to exit.

Referring back to FIG. 5, the vent assembly 100 further includes a cap130 adapted to be disposed over the plurality of barriers 118 to furtherenclose the check valve 108. Noise generated by the exhaust medium, suchas air flow, through the exhaust port opening 44 is further reduced by acombination of both the plurality of barriers 118 and the cap 130. Inone example, together the plurality of barriers 118 and the cap 130provide a tortuous flow path for the noise and exhaust medium. Saidanother way, and in one example, the plurality of barriers 118 and thecap 130 together form an enclosure around the noise, limitingtransmission of the sound through the vent assembly 100 while stillallowing the exhaust medium to be released to the atmosphere.

In addition, and in one example, a screen 132, such as a perforatedmetal screen, is disposed between the body 102 and the cap 130. Thescreen 132 is permeable, such as air, gas and fluid permeable. As such,the screen 132 further allows any exhaust medium flowing through theplurality of barriers 118 to be released to the atmosphere.

The cap 130 further includes a plurality of holes 134, each of which isadapted to receive a bolt 136 to removeably secure the cap 130 to thebody 102 of the vent assembly 100 and the body 102 to the housing 26 ofthe digital valve positioner 14. More specifically, the body 102 may bemounted to porting block housing 37, as depicted in FIG. 5, for example.While the vent assembly 100 is removably mounted to the housing 26 ofthe digital valve positioner 14 via the bolts 136, various othermounting or securing mechanisms may alternatively be used withoutdeparting from the scope of the present disclosure.

Referring now to FIGS. 8-10, a vent assembly 200 according to anotheraspect of the present disclosure is depicted. The vent assembly 200 isadapted to be operatively coupled to the digital valve positioner 14 ofFIG. 4, for example. More specifically, and like the vent assembly 100of FIGS. 2-7, the vent assembly 200 is also adapted to be operativelycoupled to the at least one exhaust port opening 44A, 44B of the digitalvalve positioner of FIG. 4, for example. Generally, the vent assembly200 includes essentially the same function and similar structure as thevent assembly 100, with some minor modifications, as explained morebelow. Generally, the vent assembly 200 includes a cap having aplurality of barriers that form an enclosure around the check valve toprevent external media from entering the exhaust port openings 44A, 44B.The cap having the plurality of barriers also provides a tortuous flowpath for the exhaust medium reducing sound through the vent assembly 200without affecting the flow capacity of the digital valve positioner 14.

For consistency, please note that parts of the vent assembly 200 ofFIGS. 8-10 that are the same as parts of the vent assembly 100 of FIGS.2-7 are similarly numbered. For example, the parts of the vent assembly200 are numbered one hundred more, e.g., 202 instead of 102, than thesame part of the vent assembly 100.

As depicted in FIGS. 8-9, the vent assembly 200 includes a body 202adapted to be operatively coupled to the at least one exhaust portopening 44A, 44B (FIG. 4) of the digital valve positioner 14. The body202 includes a bore 204. The vent assembly 200 further includes a valveseat 206 surrounding the bore 204 and a check valve 208 adapted to bedisposed within the bore 204. Like the check valve 108 of the ventassembly 100, the check valve 208 is also arranged to shift from aclosed position seated against the valve seat 206 to an open positionseated away from the valve seat 206 when an exhaust medium flows throughthe at least one exhaust port opening 44A, 44B.

The vent assembly 200 further includes a protective cover, such as a cap230, which is adapted to be removably secured to the body 202. The cap230 includes a plurality of barriers 218 extending therefrom anddisposed around the check valve 208 to enclose the check valve 208 whenthe cap 230 is secured to the body 202 of the vent assembly 200. In theexample depicted in FIGS. 9 and 10, the plurality of barriers 218 takethe form of a plurality of posts 250. Each post 250 of the plurality ofposts 250 is offset from one another to enclose the check valve 208 andto provide no line-of-sight between the external medium to the checkvalve 208, for example. As one of ordinary skill in the art willappreciate, the plurality of barriers 218 may alternatively take theshape of a variety of other forms, such as an elongate protrusion and/oran elongate protrusion that is curved, and still fall within the scopeof the present disclosure.

The cap 230 and the plurality of posts 250 are arranged to prevent anexternal medium, such as rain, wind or hail, from entering the exhaustport openings 44A, 44B through the check valve 208. In addition, the cap230 and the plurality of posts 250 are arranged to provide a tortuousflow path for the exhaust medium flowing through the vent assembly 200,reducing sound through the vent assembly 200.

As further depicted in FIGS. 9 and 10, the cap 230 includes a top face252 and a bottom face 254. The bottom face 254 includes a concavesection 256 disposed in a center area of the bottom face 254. Theconcave section 256 is adapted to receive the check valve 208 when thecheck valve 208 is in an open position, for example. The concave section256 may include a plurality of projections 257 extending radially arounda bottom surface of the concave section 256 to further accommodate thecheck valve 208, for example.

In one example, the concave section 256 further includes a centerportion 260 from which at least one projection 262 of the plurality ofprojections 257 extends. In some examples, and as depicted in FIGS. 9and 10, each projection of the plurality of projections 257 extends fromthe center portion 260 of the concave section 256. In addition, inanother example, the at least one projection 262 includes a first flatsection 264 that extends from the center portion 260, a first slopingsection 266 that extends from the first flat section 264, and a secondflat section 268 that extends from the first sloping section 266. The atleast one projection 262 further includes a second sloping section 270that extends from the second flat section 268 and a raised section 272that extends from the second sloping section 270. The raised section 272includes a side surface 274 that extends vertically from the secondsloping section 270, such as perpendicular to an end of the secondsloping section 270, and a top surface 276. The top surface 276 is flat,but may alternatively be rounded, spherical, or cylindrical in shape andstill fall within the scope of the disclosure.

As depicted in FIGS. 9 and 10, the first and second sloping sections266, 270 of the at least one projection 262 slope upwardly from thecenter portion 260 of the concave section 256, helping to form theconcave shape. For example, the first sloping section 266 slopesupwardly from the first flat section 264 and the second sloping section270 slopes upwardly from the second flat section 268. While notdepicted, one of ordinary skill in the art will appreciate that thefirst and second sloping sections 266, 270 may slope upwardly at adifferent angle from the center portion 260 and still fall within thescope of the present disclosure. In addition, each of the first andsecond flat sections 264, 268, the first and second sloping sections266, 270, and the raised section 272 may also have a length that isshorter than or longer than the length depicted in FIGS. 9 and 10 andstill fall within the scope of the present disclosure.

The plurality of barriers 218, e.g., plurality of posts 250, extendsfrom the bottom face 254 and surrounds the check valve 208. Morespecifically, the offset posts 250 provide no line-of-sight between thecheck valve 208 and an exterior of the body 202 of the vent assembly200. As a result, direct impingement of any external media, such asrain, wind, or hail, on the check valve 208 is eliminated. In addition,and like the barriers 118 of the vent assembly 100, the barriers 218 andthe posts 250, for example, are also spaced from each other to allowproper venting of exhaust medium from the digital valve positioner 14when required.

Like the body 102 of the vent assembly 100, the body 202 is also adaptedto be disposed over the at least one exhaust port opening 44A, 44B andincludes an outer end surface 206. The body 202 further defines an inlet212 and an outlet (not shown) and a plurality of apertures 216 disposedin the outer end surface 206 of the body 202 and around the bore 204.

As depicted in FIG. 8, the cap 230 may also include a plurality of holes234, each of which is adapted to receive a bolt to removeably secure thecap 230 to the body 202 of the vent assembly 200 and the body 202 to thehousing 26 of the digital valve positioner 14. More specifically, thebody 202 may be mounted to porting block housing 37 (FIG. 4), such thatthe body 202 is disposed over both exhaust port openings 44A, 44B. Whilethe vent assembly 200 is removably mounted to the housing 26 of thedigital valve positioner 14 via a bolt, various other mounting orsecuring mechanisms may alternatively be used without departing from thescope of the present disclosure.

While the vent assemblies 100 and 200 each include check valves 108,208, in one example the check valves 108, 208 are umbrella valves. Inanother example, the check valves 108, 208 are umbrella check valves.Other valves capable of achieving the same functions described aboverelative to check valves 108, 208 may alternatively be used withoutdeparting from the scope of the present disclosure.

Referring now to FIGS. 11-16, another vent assembly 300 according toanother aspect of the present disclosure is depicted. Like the ventassemblies 100, 200, the vent assembly 300 is also adapted to beoperatively coupled to a digital valve positioner 114. Morespecifically, and like the vent assemblies 100, 200, the vent assembly300 is also adapted to be operatively coupled to the at least oneexhaust port opening of the digital valve positioner 114. Generally, thevent assembly 300 includes essentially the same function and similarstructure as the vent assembly 100, with some minor modifications, asexplained more below. In addition, the digital valve positioner 114 alsoincludes essentially the same function and structure as the digitalvalve positioner 14 depicted in FIGS. 1-7, with some minormodifications, as explained in detail below.

For consistency, please note that parts of the vent assembly 300 ofFIGS. 11-16 that are the same as parts of the vent assembly 100 of FIGS.2-7 are similarly numbered. For example, the parts of the vent assembly300 are numbered two hundred more, e.g., 302 instead of 102, than thesame part of the vent assembly 100. In addition, parts of the digitalvalve positioner 114 of FIGS. 11-16 that are the same as parts of thedigital valve positioner 14 of FIGS. 2-7 are likewise similarlynumbered, e.g., numbered one hundred more than the digital valvepositioner 14.

Referring to FIGS. 11-15, the digital valve positioner 114 includes acover 116, a housing 126 and a porting block 136. The porting block 136includes one output port 138 and one supply port 140. Like the digitalvalve positioner 14, the output port 138 is operatively coupled to anactuator, such as the actuator 12, in a well-known manner. In addition,the supply port 140 is operatively coupled to a supply source, such asthe supply source 20 (FIG. 1), also in a well-known manner. As depictedin FIG. 13, the porting block 136 further includes one exhaust port 142that corresponds to the output port 138. In addition, the exhaust port142 includes an exhaust port opening 144. The porting size of the outputport 138 and the exhaust port 142 are larger than the output ports 38A,38B and exhaust ports 42A, 42B of the digital valve positioner 14 ofFIGS. 2-7 and can, therefore, accommodate higher flow capacity. Forexample, the digital valve positioner 114 can have a flow coefficient(Cv) of 6.4. As further depicted in FIGS. 11 and 12, for example, thedigital valve positioner 114 also includes a vent assembly 300 that isoperatively coupled to the exhaust port opening 144, as explained inmore detail below.

Referring now to FIGS. 14-16, the vent assembly 300 includes a body 302that is operatively coupled to the exhaust port opening 144. The body302 includes an upper portion 303 and a lower portion 305. The lowerportion 305 includes an extension adapted to be disposed in the exhaustport opening 144, as depicted in FIG. 15. The upper portion 303 includesa first bore 304A (FIG. 16) and a second bore 304B (FIG. 16) adjacent tothe first bore 304A. A first valve seat 306 surrounds the first bore304A and a first check valve 308 is disposed within the first bore 304A.In a similar manner, a second valve seat 309 surrounds the second bore304B and a second check valve 311 is disposed within the second bore304B. Both check valves 308, 311 are arranged to shift from a closedposition seated against the valve seats 306, 309 to an open positiondisposed away from the valve seats 306, 309 when an exhaust medium flowsthrough the exhaust port opening 144. Said another way, the check valves308, 311 are normally biased in the closed positions depicted in FIGS.14 and 16, and will shift to an open position when exhaust medium flowsinto the check valves 308, 311, pushing the check valves 308, 311 awayfrom the valve seats 306, 309 and allowing an exhaust medium to ventthrough the vent assembly 300. The normally closed position of the checkvalves 308, 311 helps protect against the ingress of external media,into the check valves 308, 311, the exhaust port opening 144, and, thus,the digital valve positioner 114, as explained more below. Like the ventassembly 100, the body 302 further includes an outer end surface 310, aportion of which may form the valve seats 306, 309.

As further depicted in FIG. 16, the body 302 of the vent assembly 300further includes an inlet 312 and an outlet 314. The bores 304A, 304Bare disposed between the inlet 312 and the outlet 314, and a pluralityof apertures 316 is disposed in the outer end surface 310 of the body,around the bores 304A, 304B. The check valves 308, 311 are positioned inthe closed position, such that when the exhaust medium flows through theat least one exhaust port opening 144, the exhaust medium is directedthrough the plurality of apertures 116 surrounding the bores 304A, 304Band into the check valves 308, 311. This shifts the check valves 308,311 to the open position to release the exhaust medium to theatmosphere.

The vent assembly 300 further includes an enclosure disposed around thecheck valves 308, 311. In one example, the enclosure comprises aplurality of barriers 318. The plurality of barriers 318 is disposedaround the check valves 308, 311 and positioned to enclose the checkvalves 308, 311. In addition, the plurality of barriers 318 is arrangedto prevent an external medium, such as wind, rain, dirt or any otherproduct from the environment, from entering the exhaust port opening 144through the check valves 308, 311. Like the plurality of barriers 118 ofthe vent assembly 100, the plurality of barriers 318 protect the checkvalves 308, 311 from any external media by enclosing the check valves308, 311. The enclosure still allows for flow of the exhaust mediumwithout reducing or affecting the flow capacity of the digital valvepositioner 114.

Also like the vent assembly 100, and in the example of FIGS. 14-16, eachbarrier 318 of the plurality of barriers 318 includes an elongateprotrusion 320 extending from the outer end surface 310 of the body 202.As depicted in FIG. 14, for example, each elongate protrusion 320 mayalso be curved. Further, each elongate protrusion 320 includes a firstend 322 and a second end 324. At least one of the first and second ends322, 324 of one protrusion 320 overlaps with one or more of the firstand second ends 322, 324 of another protrusion 320 to enclose the checkvalves 308, 311. The overlapping protrusions 320 of the plurality ofbarriers 318 provide no line-of-sight between the check valves 308, 311and an exterior of the body 302 of the vent assembly 300. As a result,direct impingement of any external media, such as rain, wind, or hail,on the check valves 308, 311 is eliminated. As further depicted in FIGS.14 and 15, the barriers 318 are also spaced from each other to allowproper venting of exhaust medium from the digital valve positioner 114when required.

While in the foregoing example, each barrier 318 of the plurality ofbarriers 318 includes an elongate protrusion 320, each barrier 318 ofthe plurality of barriers 318 may alternatively take the shape of avariety of other forms and still fall within the scope of the presentdisclosure. For example, each barrier 318 of the plurality of barriers318 may alternatively form a discrete post, each of which is offset fromanother post such that no line-of-sight is provided between the checkvalves 308, 311 and an exterior of the body 302 of the vent assembly300. In yet another example, each barrier 318 of the plurality ofbarriers 318 may take the form of any other overlapping or offset shape,size or structure and still fall within the scope of the presentdisclosure. In yet another example, each barrier 318 may alternativelyextend from an inside surface of a cap 330, as opposed to the outer endsurface 310 of the body 302 as depicted, for example, in FIG. 14, andstill fall within the scope of the present disclosure.

Further, noise generated by the exhaust medium flowing through theexhaust port opening 144, for example, is reduced by directing theexhaust medium into the plurality of barriers 318. More specifically,the check valves 308, 311 direct the exhaust medium radially into theplurality of barriers 318, which prevents a high velocity exhaust mediumfrom forming at an exit of the exhaust port 142. The high velocityexhaust medium instead is shifted to an area of the check valves 308,311 that together with the plurality of barriers 318 slow the exhaustmedium before it exits to the atmosphere. The plurality of barriers 318limit the transmission of sound through the vent assembly 100 whilestill allowing the exhaust medium to exit.

Like the vent assembly 100, and in one example, the enclosure of thevent assembly 300 may further include the cap 330 that is adapted to bedisposed over the plurality of barriers 318 to further enclose the checkvalves 308, 311. Noise generated by the exhaust medium flowing throughthe exhaust port opening 144 is further reduced by a combination of boththe plurality of barriers 318 and the cap 330. In one example, togetherthe plurality of barriers 318 and the cap 330 provide a tortuous flowpath for the noise and exhaust medium. Said another way, and in oneexample, the plurality of barriers 318 and the cap 330 together form anenclosure around the noise, limiting transmission of the sound throughthe vent assembly 300 while still allowing the exhaust medium to bereleased to the atmosphere.

In addition, a screen 332 (FIG. 15), such as a perforated metal screen,may be disposed between the body 302 and the cap 330. The screen 332 ispermeable, such as air, gas and fluid permeable. As such, the screen 332helps allow the exhaust medium flowing through the plurality of barriers318 to be released to the atmosphere.

The cap 330 further includes a plurality of holes 334, each of which isadapted to receive a bolt 336 to removeably secure the cap 330 to thebody 302 of the vent assembly 300 and the body 302 to porting blockhousing 137. While the vent assembly 300 is removably mounted to thedigital valve positioner 114 via the bolts 336, various other mountingor securing mechanisms may be alternatively be used without departingfrom the scope of the present disclosure. Like the vent assemblies 100,200, in one example, the check valves 308, 311 of the vent assembly 300are umbrella valves. In another example, the check valves 308, 311 ofthe vent assembly 300 are umbrella check valves.

Thus, the plurality of barriers 318 surrounding the check valves 308,311 effectively prevent an external medium from entering the checkvalves 308, 311 and provide a tortuous flow path for the exhaust mediumflowing from a high capacity digital valve positioner 114 having a flowcoefficient (Cv) of 6.4. Said another way, the vent assembly 300 canaccommodate the higher flow capacity of the high capacity digital valvepositioner 114 and still effectively both prevent exhaust media fromentering the check valves 308, 311 and reduce sound through the ventassembly 300.

While not depicted in any of the foregoing figures, one of ordinaryskill in the art will appreciate that more than two check valves may beincluded in the body of a vent assembly and still fall within the scopeof the present disclosure. For example, another alternative ventassembly may include a body having three bores, each of which includes avalve seat surrounding the bore and a check valve disposed within thebore and one of a plurality of barriers or plurality of postssurrounding each check valve and forming an enclosure around the same.Such a configuration would provide even further protection againstingress of external media into the digital valve positioner withoutaffecting the flow capacity and also provide further noise reduction.

In view of the foregoing, one of ordinary skill in the art willunderstand that all the vent assemblies 100, 200 and 300 of the presentdisclosure may protect internal components of a digital valve positioner14, 114 and reduce noise levels of exhaust media by providing a ventassembly 100, 200, 300 comprising at least one check valve 108, 208,308, 311 surrounded by a plurality of barriers 118, 218, 318. The ventassemblies 100, 200 and 300 may further direct exhaust medium into theat least one check valve 108, 208, 308, 311 and through the plurality ofbarriers 118, 218, 318, reducing the sound of exhaust medium flowingthrough the vent assembly 100, 200, 300. The vent assemblies 100, 200and 300 may further protect the digital valve positioner 14, 114 fromexternal media by preventing an external medium from entering the checkvalves 108, 208, 308, 311 via the plurality of barriers 118, 218, 318surrounding the check valves 108, 208, 308, 311 without affecting theflow capacity of the digital valve positioner 14, 114.

In addition, one of ordinary skill in the art will further understandthat the design and distribution of the plurality of barriers 118, 218,318 not only serve to protect each vent assembly 100, 200, 300 fromdirect impact from the environment and reduce noise levels, but alsoprevent significant pooling of water in the area of the check valves108, 208, 308, 311 and the plurality of barriers 118, 218, 318. Bypreventing significant pooling of water, any freezing of such water isalso prevented should the ambient temperature drop below freezing. Inaddition, each vent assembly 100, 200, 300 is self-draining, independentof orientation, by allowing the rain water, for example, that enters thearea of the plurality of barriers 118, 218, 318 to pin ball through anddrain out the opposite side of the vent assembly 100, 200, 300.

In view of the foregoing, one of ordinary skill in the art will furtherunderstand that each vent assembly 100, 200 and 300 may direct exhaustmedia through a plurality of apertures 116, 216 disposed around a bore104, 204 of a body 102, 202, 302 of the vent assembly 100, 200, 300,into the check valves 108, 208, 308, 311 disposed within the bores 104,204 and then radially outward into the plurality of barriers 118, 218,318. One of ordinary skill in the art will also understand that eachvent assembly 100, 200, 300 may reduce the sound level of exhaust mediumflowing through the vent assemblies 100, 200, 300 by providing atortuous flow path in both a cap 130, 230, and 330 and the plurality ofbarriers 118, 218, 318. One of ordinary skill will further understandthat preventing external medium from entering the check valves 108, 208,308, 311 without affecting the flow capacity of the digital valvepositioner 14, 114 includes enclosing the check valve 108, 208, 308, 311via both the cap 130, 230, 330 and the plurality of barriers 118, 218,318.

Throughout this specification, plural instances may implementcomponents, operations, or structures described as a single instance.Although individual operations of one or more methods are illustratedand described as separate operations, one or more of the individualoperations may be performed concurrently, and nothing requires that theoperations be performed in the order illustrated. Structures andfunctionality presented as separate components in example configurationsmay be implemented as a combined structure or component. Similarly,structures and functionality presented as a single component may beimplemented as separate components. These and other variations,modifications, additions, and improvements fall within the scope of thesubject matter herein.

As used herein any reference to “one example” or “an example” means thata particular element, feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodiment.The appearances of the phrase “in one example” in various places in thespecification are not necessarily all referring to the same example.

Some examples may be described using the expression “coupled” and“connected” along with their derivatives. For example, some examples maybe described using the term “coupled” to indicate that two or moreelements are in direct physical or electrical contact. The term“coupled,” however, may also mean that two or more elements are not indirect contact with each other, but yet still cooperate or interact witheach other. The examples are not limited in this context.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

In addition, use of the “a” or “an” are employed to describe elementsand components of the embodiments herein. This is done merely forconvenience and to give a general sense of the description. Thisdescription, and the claims that follow, should be read to include oneor at least one and the singular also includes the plural unless it isobvious that it is meant otherwise.

This detailed description is to be construed as examples and does notdescribe every possible embodiment, as describing every possibleembodiment would be impractical, if not impossible. One could implementnumerous alternate embodiments, using either current technology ortechnology developed after the filing date of this application.

While various embodiments have been described above, this disclosure isnot intended to be limited thereto. Variations can be made to thedisclosed examples that are still within the scope of the appendedclaims.

What is claimed:
 1. A digital valve positioner for use with an actuator,the digital valve positioner comprising: a housing; at least one exhaustport opening formed in the housing; a vent assembly operatively coupledto the at least one exhaust port opening, the vent assembly including: abody operatively coupled to the at least one exhaust port opening, thebody including a bore; a valve seat surrounding the bore; and a checkvalve disposed within the bore, the check valve arranged to shift from aclosed position seated against the valve seat to an open positiondisposed away from the valve seat when an exhaust medium flows throughthe at least one exhaust port opening; and a cap removably secured tothe body, the cap having a plurality of barriers extending therefrom anddisposed around the check valve to enclose the check valve, the cap andthe plurality of barriers arranged to prevent an external medium fromentering the check valve and to provide a tortuous flow path for theexhaust medium reducing sound through the vent assembly.
 2. The digitalvalve positioner of claim 1, the cap comprising a top face and a bottomface, the bottom face having a concave section adapted to receive thecheck valve when the check valve is in an open position, the pluralityof barriers comprising a plurality of posts, the plurality of postsextending from the bottom face and surrounding the check valve.
 3. Thedigital valve positioner of claim 2, each post of the plurality of postsis offset from each of the other posts to enclose the check valve and toprovide no line-of-sight between the external medium and the checkvalve.
 4. The digital valve positioner of claim 1, the body disposedover the at least one exhaust port opening and including an outer endsurface.
 5. The digital valve positioner of claim 4, the body definingan inlet and an outlet, the bore disposed between the inlet and theoutlet, and a plurality of apertures disposed in the outer end surfaceand around the bore.
 6. The digital valve positioner of claim 1, the atleast one exhaust port opening comprising two exhaust port openings, thebody disposed over the at least two exhaust openings.
 7. The digitalvalve positioner of claim 1, the check valve comprising an umbrellacheck valve.
 8. An actuator comprising: an actuator housing; and thedigital valve positioner of claim 1, wherein the digital valvepositioner is operatively connected to the actuator housing to convertan input signal to a pneumatic output pressure to the actuator.